1. Field of the Invention
The present invention relates to an article pickup apparatus and an article pickup method for recognizing a position and a posture of an article randomly piled in a three-dimensional space and picking up the recognized article using a robot.
2. Description of the Related Art
As an apparatus of this type, there is known an apparatus configured to recognize a position of an article by applying pattern matching to a two-dimensional image obtained by imaging articles randomly piled using a camera or a three-dimensional point set obtained by measurement using a three-dimensional measurement instrument. This apparatus is described, for example, in Japanese Laid-open Patent Publication No. 2011-179909 (JP2011-179909A).
In the apparatus described in JP2011-179909A1, while a three-dimensional model pattern of an article is previously acquired from a CAD model or the like, surfaces of articles in a three-dimensional space are measured using a three-dimensional measurement instrument and a three-dimensional point set (a distance image) is acquired, and then the three-dimensional point set is divided into partial regions surrounded by an edge extracted from the three-dimensional point set. Then, initially, one of the partial regions is set as an article region, and both matching processing of the three-dimensional model pattern for the article region and update processing for adding another partial region to the article region are repeated to measure positions and postures of the articles.
However, in the apparatus described in JP2011-179909A, it is necessary to previously prepare a three-dimensional model pattern for each type of article, and therefore, time and effort are needed. In particular, regarding a large number of types of articles, it is necessary to prepare model patterns for the number of types and therefore, much time and effort are needed. Further, for an indefinitely shaped article, it is inherently difficult to prepare a model pattern, resulting in difficulty in an application thereof. Further, while articles are randomly piled, it is difficult to obtain three-dimensional point sets sufficient to the extent that a three-dimensional posture of an article can be determined via pattern matching.